Development of sensors or probes that can be used to detect the trace vapor of organic amines represents one of the active research fields in chemistry and materials science, particularly those related to the emerging nanoscience and nanotechnology. Volatile amines have been heavily used in various areas ranging from chemical and pharmaceutical to food industries. Some of the amines, like hydrazine, have also been used in the military as fuel additives in rocket and fighter jet propulsion systems. Detecting these amines with high sensitivity is not only critical to air pollution monitoring and control but also may provide expedient ways for quality control of food and even medical diagnosis of certain types of disease. For example, in diagnosing uremia and lung cancer, released biogenic amines are commonly used as biomarkers.
Although much success has been achieved for detection of amines in solutions using various types of sensors, the vapor-based detection of gaseous amines still remains challenging. This challenge is largely due to the limited availability of sensory materials that enable vapor detection with both high sensitivity and selectivity. Fluorescent sensing and probing based on organic sensory materials represents a unique class of detection techniques that usually provide a simple, expedient way for chemical detection and analysis. However, there are not many organic materials available that are sufficiently fluorescent in the solid state and suited for use as sensory materials in vapor detection. These materials may be strongly fluorescent in molecular state in solutions. Moreover, compared to the more common p-type (i.e., electron donating) materials, which are suited for sensing oxidative reagents like nitro-based compounds, the availability of n-type organic materials (i.e., electron accepting, and suited for sensing reducing reagents like amines) is much more limited.